SAN DIEGO (AP)-An injury plague has struck San Diego Chargers left tackles.

Presumptive starter Brandyn Dombrowski missed his second straight practice on Monday, the same day it was announced that current backup Nick Richmond will have arthroscopic knee surgery and will be out two weeks. Veteran tackle Tra Thomas is out another week after having the same procedure last week.

That left guard Tyronne Green to work with the first team at left tackle, a position he first assumed on Saturday.

Left tackle Marcus McNeill is holding out in a contract spat.

"We've got some nagging injuries there, but it's funny how things like that happen and it ends up making you better," coach Norv Turner said. "Tyronne Green has moved over there, and it might be his most natural position. What you find out is that you have guys who, throughout the course of the season, can contribute in a number of different spots."

Receiver Legedu Naanee was pulled from Monday morning's practice with a groin injury that sidelined him last week. Guard Scott Mruczkowski re-aggravated an ankle injury that kept him out last week as well.

NOTES: The Chargers signed offensive lineman Cameron Stephenson, who last played in the NFL for the Jacksonville Jaguars. - San Diego waived receiver Ernest Smith and offensive lineman Corey Clark chose to leave the team.